Nasal Melanophoroma in a Captive Green Iguana (Iguana Iguana).

Green iguanas are arboreal lizards, common as pet animals and in captivity. Knowledge of neoplasms in iguanas is scarce, and a challenge to their prevention, treatment, and prognosis. A captive green iguana showed a pigmented nasal exophytic neoplasm. Tumor cells were spindle-shaped to epithelioid with a variable amount of dark-brown or black granular melanin within the cytoplasm, and also presented cytoplasmic positivity for Melan-A and S100. Transmission electron microscopy evidenced intracytoplasmic melanosomes and premelanosomes and provided a definitive diagnosis of a nasal melanophoroma. Full characterization of the clinicopathological and ultrastructural features of the melanophoroma may contribute to the limited knowledge concerning cutaneous neoplasms in green iguanas.

PEComa of the nose: report of a case with immunohistochemical and ultrustructural studies and a review of the literature.

PEComas are a family of mesenchymal neoplasms that have in common the presence of a unique cell type, the perivascular epithelioid cell (PEC). PECs uniquely exhibit a distinct immunophenotype with expression of both melanocytic, particularly HMB-45, and myogenic markers. Nasal PEComas are exceedingly rare. To date, 14 cases have been described in the literature and with the exception of 6 cases, the rest consistently lack epithelioid cells and HMB-45 expression and are best classified as nasal hamartomas or angioleiomyomas with an adipocytic component. Nasal PEComas may closely resemble malignant melanomas since both entities share many morphologic, immunohistochemical, ultrastructural and clinical features. The distinction is of paramount importance as melanomas tend to display an aggressive behaviour with associated poor outcome. Herein, we report a case of nasal PEComa in a 19 year girl, focusing on the importance of light microscopic, immunohistochemical and ultrastructural features in accurately establishing the diagnosis.

Ultrastructual morphology of juvenile psammomatoid ossifying fibroma.

We investigated the ultrastructural morphology of the hard tissue in a fibro-osseous lesion. Bone samples were obtained from a juvenile psammomatoid ossifying fibroma and were observed under a scanning electron microscope. The lesion had a spongy lamellar structure containing bony tissue. On histological examination, resorbing preexisting lamellar bone associated with a large number of cathepsin K-positive osteoclasts was confirmed. Scanning electron microscopy revealed the bony material to have a cribriform structure and to indicate resorption related to osteoclasts throughout the tumor. These characteristic findings revealed the presence of active bony reconstruction and destruction in this lesion. The spongy calcified structure observed by scanning electron microscopy expressed the characteristic ground glass appearance in computed tomography of this patient. This remarkable activation of osteoclasts may deeply relate to characteristic calcified structure in this lesion. Observation of hard tissue structure under a scanning electron microscope may shed light on the pathology of fibro-osseous lesions in the head and neck.

[Extracranial meningioma: morphological and histogenetical aspects and relations with perineurioma].

The clinicomorphological, immunohistochemical, and ultrastructural characteristics of 11 cases of extracranial meningioma versus 79 soft tissue perineuriomas were studied. There were significant similarities (cell morphology, immunoprofile, ultrastructural features of perineurial differentiation) of both entities. Considering the point of view that arachnoid and perineurial cells are anatomically, embryologically, and functionally related, it is most possible that extracranial meningiomas may be derived from perineurial cells (or their progenitor cell) rather than from displaced arachnoid cells.

Descriptive study of enzootic nasal adenocarcinoma in goats in southwestern China.

This is the first report on enzootic nasal adenocarcinoma (ENA) in goats (Nanjiang Yellow goats and Jianyang Big-ear Black goats) in southwestern China. The clinical, histological and ultrastructural features of ENA in goats were described. From July 2007 to May 2009, 21 cases of ENA in goats, from 6 months to 8 years old, were diagnosed solely in one big herd. Clinically, the affected goats showed nasal discharge, facial swelling, sneezing, stertorous breathing and weight loss. Tumours that originated from the ethmoid area of the nasal cavity were unilateral (18/21) or bilateral (3/21). All tumours were classified as low grade adenocarcinomas by histopathological examination and were displayed a combination of tubular and papillary growth. No metastases were detected in regional lymph nodes, brain or other organs. Ultrastructurally, virus-like particles with an average diameter between 80 and 110 nm were observed in 5/7 examined tumours.

Divergent myoid, neuroendocrine, and perineural differentiation in a nasal tumor of a patient with Carney complex.

A 39-year-old woman with Carney complex presented with a stroke of undetermined etiology. Computed tomography showed bilateral thalamic infarctions and also an unsuspected multicompartmental cystic neoplasm that had eroded the anterior clivus and extended forward into the nasopharynx. Histologically, the mass appeared benign and was composed of spindle cells and multiple foci of striated muscle. Immunohistochemically, the spindle cells were strongly reactive for S-100 protein and to a lesser extent for CD57, collagen IV, neuron-specific enolase, smooth muscle actin, epithelial membrane antigen, and glut-1. The striated muscle cells were positive for desmin and myogenin. The MIB-1 labeling index was 0.5%. Ultrastructural examination was necessary to reveal the full extent of divergent differentiation. Ultrastructurally, the spindle cells showed divergent differentiation along several cell lines, including smooth muscle, neuroendocrine, hybrid smooth muscle-neuroendocrine, perineural-like cells, and striated muscle. The occurrence of this unique lesion in a patient with the Carney complex raises the possibility that it may be a rare component of the syndrome.

Myofibroblastic sarcoma of the nasal cavity and paranasal sinus: a clinicopathologic study of 6 cases and review of the literature.

OBJECTIVE: We describe the clinicopathologic features of 6 cases of myofibroblastic sarcoma (MS) occurring in the nasal cavity and paranasal sinus. STUDY DESIGN: The paraffin-embedded tissues of 6 cases of MS were stained immunohistochemically and examined by electron microscopy. RESULTS: Clinically, a painless enlarging mass was the most common symptom, followed by the nasal obstruction, epistaxis, copious rhinorrhea, and proptosis. Histologically, the tumors showed a diffusely infiltrative growth pattern and consisted mainly of spindle cells with abundant eosinophilic cytoplasm. The hypocellular myxoid areas and the hypercellular fibrous areas were identified. Immunohistochemically, all 6 tumors were positive for vimentin, alpha-smooth muscle actin, calponin, and fibronectin. Ultrastructural examination in 3 cases showed characteristic features of myofibroblast. Follow-up in 6 patients revealed high local recurrence rate (6 out of 6). CONCLUSION: Myofibroblastic sarcoma of the nasal cavity and paranasal sinus exhibit diverse histologic appearances and a strong aggressive behavior.

Olfactory neuroepithelioma: an immunohistochemical and ultrastructural study.

Three cases of olfactory neuroepithelioma are presented in this report. Histologically, these tumors were composed of small cells with round to oval, relatively hyperchromatic nuclei and scanty cytoplasm. The tumor cells were occasionally observed in tubular formations or rosette-like arrangements. Immunohistochemically, the tumor cells showed a positive reaction for cytokeratin AE1, cytokeratin CAM5.2, Ber-EP4, antisynaptophysin and anti-S100 protein in all cases. In two cases, LH-RH was detected in the tumor cells. Ultrastructurally, the tumor cells had the differentiation features of olfactory epithelium. Olfactory neuroepithelioma is a rare occurrence and it can be very difficult to distinguish olfactory neuroepithelioma from small cell carcinoma, neuroendocrine carcinoma and so-called "olfactory neuroblastoma" on the basis of hematoxylin and eosin stained sections alone. In controversial cases, a diagnosis of olfactory neuroepithelioma must be substantiated by ultrastructural and immunohistochemical findings, particularly regarding the detection of Ber-EP4 and LH-RH immunoreactivity.

Epstein-barr virus induced cellular changes in nasal mucosa.

UNLABELLED: A 21-year-old man presented with nasal obstruction of the right nasal fossa of 1 year duration. Nasal endoscopy revealed in the right inferior turbinate head a rounded neoplasm about 1 cm in diameter. Cytologic study of a nasal scraping specimen disclosed numerous clusters containing columnar cells with cytomegaly, prominent multinucleation, markedly sparse shortened cilia; the cytoplasm contained an acidophil area and a small round area that stained poorly; cells with a large intracytoplasmic vacuole that was acidophil and PAS+. Serology tests using the nested polymer chain reaction (PCR) technique on serum, nasal and pharyngeal smears revealed an Epstein-Barr virus (EBV) infection that was confirmed at electron microscopy. The clinical and cytological features resolved 19 months after the initial evaluation. CONCLUSION: The authors advise carrying out clinical (endoscopy, serology, etc.) evaluation of all endonasal neoplasms and to routinely perform cytological study on nasal scraping specimens. When samples test positive for EBV, nasal and nasopharyngeal endoscopy should be performed regularly to detect possible evidence for nasopharyngeal carcinoma (NPC).

Enzootic nasal adenocarcinoma of sheep in Slovenia.

SUMMARY Clinicopathological and electron microscopical findings of eight cases of enzootic nasal adenocarcinoma of sheep, diagnosed solely in one big flock in Slovenia between years 2001 and 2003 are described. All affected sheep were female, their mean age was 4.5 +/- 1.5 years and they either belonged to the Istrian pramenka breed (five sheep) or were crossbreeds (three sheep). Tumours that arose from the ethmoid area of the nasal cavity were unilateral in six cases (75%) and bilateral in two cases (25%). All tumours were classified as adenocarcinomas by histopathological examination and they displayed either a combination of tubular and papillary growth or less often solely tubular proliferation. No metastases were detected in regional lymph nodes, brain or other organs. Electron microscopical studies performed on the reprocessed paraffin-embedded tissues revealed the presence of the virus-like particles with an average diameter between 70 and 90 nm.

Malignant melanoma with neuroendocrine differentiation: clinical, histological, immunohistochemical and ultrastructural features of three cases.

AIM: To document the clinical, histological, immunohistochemical and ultrastructural features of three malignant melanomas showing neuroendocrine differentiation. METHODS AND RESULTS: Three patients, two with primary cutaneous melanoma and one with nasal mucosal melanoma, subsequently developing or simultaneously presenting with metastatic malignant melanoma, were studied by conventional histological technique, immunohistochemistry of formalin-fixed paraffin-wax embedded tissues, and electron microscopy of epoxy-resin-embedded tumour tissue. Tumours showed either small cell or conventional malignant melanoma cell morphology. One of the three primary melanocytic lesions (the nasal melanoma) exhibited neuroendocrine differentiation immunohistochemically. All three metastatic malignant melanomas showed, in varying combinations, immunohistochemical and ultrastructural evidence for neuroendocrine differentiation: they were positive for the melanocytic markers, S100 protein, HMB-45, Melan-A and tyrosinase, and the neuroendocrine markers chromogranin, synaptophysin and neurofilament protein. Ultrastructural study in two of the metastases revealed neuroendocrine granules but no lattice-bearing melanosomes. CONCLUSIONS: The cases described are the most comprehensively investigated malignant melanomas showing neuroendocrine differentiation to date, and the first to document neuroendocrine differentiation ultrastructurally in these tumours. Malignant melanoma with neuroendocrine differentiation therefore needs to be recognized among the other, better known variants of malignant melanoma.

Sinonasal acinic cell carcinoma: a clinicopathologic study of four cases.

BACKGROUND: Acinic cell carcinoma is a low-grade malignant epithelial salivary gland neoplasm with a predilection for the parotid gland. To date, only 11 cases of sinonasal acinic cell carcinomas have been reported in the English-language literature. We present the clinicopathologic features of four sinonasal acinic cell carcinomas. METHODS: The demographic data and pathologic material of four patients with sinonasal acinic cell carcinoma identified from the files of the Department of Pathology at The University of Texas M. D. Anderson Cancer Center between 1984 and 2002 were reviewed. RESULTS: The four patients were two men and two women, with an age range of 42 to 65 years (mean, 54 years). The patients were initially seen with unilateral nasal obstruction. Histologically, all tumors were composed of round to ovoid cells with clear and/or basophilic granular cytoplasm and round, hyperchromatic, small, eccentrically located nuclei. The growth pattern was lobular, solid, and follicular. Histochemically, periodic acid-Schiff diastase-resistant granules were demonstrated in all cases. All patients were treated surgically. In addition, one patient received postoperative radiation. All patients are alive and well, with follow-up from 4 to 17 years. CONCLUSIONS: Sinonasal acinic cell carcinoma is a distinct low-grade carcinoma that can be distinguished from other neoplasms by light microscopy and histochemical staining methods. Pathologists and surgeons should be aware of the occurrence of this type of salivary gland neoplasm in the sinonasal tract.

In vivo and in vitro effects of macrolide antibiotics on mucus secretion in airway epithelial cells.

To examine the in vivo effects of macrolide antibiotics on mucus hypersecretion, we induced hypertrophic and metaplastic changes of goblet cells in rat nasal epithelium by intranasal instillation of ovalbumin (OVA) in OVA-sensitized rats and by intranasal LPS instillation. Oral administration of clarithromycin (CAM) (5-10 mg/kg) significantly inhibited OVA- and LPS-induced mucus production and neutrophil infiltration, whereas josamycin and ampicillin showed no effect. In vitro effects of macrolide antibiotics on airway epithelial cells were examined using NCI-H292 cells and human nasal epithelial cells cultured in air-liquid interface. Mucus secretion was evaluated by ELISA using anti-mucin monoclonal antibodies (anti-MUC5AC and HCS18). CAM and erythromycin significantly inhibited spontaneous and tumor necrosis factor-alpha (20 ng/ml)-induced mucus secretion from NCI-H292 cells at 10-6 to 10-7 M and from human nasal epithelial cells at 10-4 to 10-5 M. MUC5AC messenger RNA expression was also significantly inhibited. These results indicate that the 14-member macrolide antibiotics, CAM and erythromycin, exert direct inhibitory effects on mucus secretion from airway epithelial cells and that they may be useful for the treatment of mucus hypersecretion caused by allergic inflammation and LPS stimulation.

Neurothekeoma celular: Presentación de un caso / Cellular neurothekeoma. A one-case presentation

Se presenta un caso de neurothekeoma calular en una mujer de 38 años, cuyo asiento de la lesión tumoral es en el vestíbulo de la fosa nasal izquierda, el cual se resecó completamente. Se describe el caso por ser un tumor de reciente caracterización, raro, tanto en nuestro medio como en la literatura médica internacional revisada(AU)

Neurothekeoma celular: Presentación de un caso / Cellular neurothekeoma. A one-case presentation

Se presenta un caso de neurothekeoma calular en una mujer de 38 años, cuyo asiento de la lesión tumoral es en el vestíbulo de la fosa nasal izquierda, el cual se resecó completamente. Se describe el caso por ser un tumor de reciente caracterización, raro, tanto en nuestro medio como en la literatura médica internacional revisada(AU)

A case of neurothekeoma calular is presented in a 38 year-old woman whose seat of the lesion tumoral is in the lobby of the grave nasal left, which was dried up completely. The case is described to be a tumor of recent characterization, strange, as much in our means as in the revised international medical literature(AU)

An ultrastructural and immunohistochemical study of olfactory neuroepithelioma with rhabdomyoblasts.

A rare case of olfactory neuroepithelioma with rhabdomyoblasts in a 61-year-old man was investigated using electron microscopic and immunohistochemical methods. A large tumor enhanced by gadolinium-diethylenetriamine pentaacetic acid (DTPA) was demonstrated on magnetic resonance imaging (MRI), located within the anterior cranial fossa without bone destruction. The tumor mostly consisted of small cells with scant cytoplasm. Tubular rosettes were often found. Immunoreactivity for cytokeratin and epithelial membrane antigen (EMA) was strongly positive. Most of the tumor cells were shown to be positive for neuron-specific enolase (NSE) and vimentin and weakly positive for synaptophysin and S-100. Rhabdomyoblasts, which showed oval cells with abundant eosinophilic cytoplasm and a nucleus sometimes displaced toward the periphery of the cell body, were frequently intermingled with the tumor cells. The immunoreactivity for myoglobin was frequently positive in these oval cells. The MIB-1 index showed high values, of 20%-40%. About 10% of the tumor cells revealed positivity for p53 protein and vascular endothelial growth factor (VEGF). Ultra-structurally, numerous junctional complexes were observed between cell bodies and processes. The cell processes frequently contained numerous microtubules. There were sometimes numerous filaments with small aggregates of Z-band material and thick filament-ribosomal complexes in the oval cells. They were concluded to be consistent with rhabdomyoblasts on light microscopic and immunohistochemical findings.

Olfactory neuroepithelioma in a dog: an immunohistochemical and electron microscopic study.

A case of olfactory neuroepithelioma was investigated electron microscopically and immunohistochemically. The tumor mass was found in the nasal cavities of a 10-year-old female dog, which showed epistaxis, nasal discharge and facial swelling. The tumor tissue consisted of tubular structure of cuboidal to columnar cells and compactly arranged nests of small cells surrounded by a fibrovascular stroma. Mitotic figures were frequently observed. Immunohistochemically, the tumor cells frequently showed positive for neurofilament protein, synaptophysin and/or carnosine in addition to keratin. Ultrastructurally, tight junction was observed between the tumor cells. No dense-cored secretory granules were shown in the tumor cells. These findings indicated that the present tumor had neuronal and epithelial features probably originating from the olfactory epithelium.

Immunohistochemical and ultrastructural studies of 2,6-dimethylaniline-induced nasal proliferative lesions in a rat two-stage nasal carcinogenesis model initiated with N-bis(2-hydroxypropyl)nitrosamine.

Proliferative lesions induced by 2,6-dimethylaniline (DMA) in a two-stage rat nasal carcinogenesis model were immunohistochemically and ultrastructurally investigated. Male F344 rats received diet containing 3,000 ppm DMA for 52 weeks after initiation with a single subcutaneous injection of 2400 mg/kg of N-bis(2-hydroxypropyl)nitrosamine (DHPN). Histopathologically, proliferation of Bowman's glands, glandular hyperplasias, dysplastic foci, adenomas, and carcinomas were observed in treated rats. These nasal lesions mostly arose in the olfactory mucosa of the nasal cavity. Immunohistochemically, they were positive for cytokeratin and/or collagen type IV antibodies. Ultrastructurally, intracytoplasmic dense secretory granules (200-850 nm in diameter), identical to those in normal Bowman's glands, were observed in all the lesions, providing further support from an origin from these glands. Based on their cellular characterization, growth pattern and/or proliferative activity, two morphological continua were evident, one from dysplastic foci to carcinomas and the other from proliferation of Bowman's glands to glandular hyperplasias and adenomas. These results suggest that dysplastic foci arise from Bowman's glands and progress to carcinomas, while proliferation of Bowman's glands result in glandular hyperplasias and adenomas.

Structural and ultrastructural study of the anterior portion of the nasal septum and inferior nasal concha.

We used scanning electron microscopy to study and compare the histologic and ultrastructural aspects of the mucosa of the anterior portion of the septum (APS) and the anterior portion of the inferior concha (APINC) in 10 healthy adults and 10 cadavers. We found that (1) in most cases, the types of epithelium were generally the same in both areas--pseudostratified cylindrical ciliated epithelium with goblet cells (respiratory epithelium), stratified cuboidal epithelium, and stratified squamous nonkeratinized epithelium; (2) the APINC had more respiratory epithelium than the APS; (3) the APS had more squamous epithelium than the APINC; (4) the basement membrane of the APINC was thicker than that of the APS; (5) moderate chronic inflammatory infiltrate was more common in the APINC, and mild infiltrate was more common in the APS; and (6) the APINC had more mucous glands and the APS had more serous glands.